Wet cell batteries are used in a variety of applications, including automobiles, boats, recreational vehicles, backup power supply purposes and the like. Such batteries are used in a wide variety of climatic conditions ranging from extremely hot dry climates to frigid climates, all of which place a great deal of stress on such a power source and frequently result in discharge of such batteries. Consequently, frequent recharge of such batteries is necessary in order to maintain maximum power output from the batteries and insure proper operation of other systems which depend upon such electrical power sources.
Frequently when wet cell batteries are used in vehicles such as automobiles, the automobile supplies generation power for the purpose of recharging the battery. In many applications, however, recharging through the primary power plant of the vehicle is not possible and consequently a battery charger must be used from time to time in order to restore the storage battery to its full potential. An example of such use might be in connection with supplying power to recreational vehicles where there is little or no opportunity to recharge the battery. A battery charger then has to be applied to the storage battery for a period of time to restore the charge. Frequently, inexperienced people must connect such battery chargers to the storage battery and have little understanding of the method of connecting the charger to the storage battery with the result that the power leads from the battery charger are frequently placed on the improper terminals of the battery with the attendant possibility of damage to the battery charger.
Further, certain applications of storage battery power require that the battery be maintained at an optimum level at all times. This requires that the battery charger be connected to the battery for extended periods of time. If the charger is connected to a storage battery for an extended period of time, there is always the risk that the battery will become overcharged if proper observation is not maintained by an operator. If a battery is overcharged, it may be damaged through depletion of the electrolyte from overheating. Overcharging can also generate excess hydrogen gas. Excess hydrogen gas can lead to a dangerous explosion if there are any sparks in the vicinity of the storage battery while the hydrogen gas is being generated through the recharging process.
Some attempts have been made to provide circuitry for permanent connection of a battery charger to a storage battery for recharging purposes. However, many of these attempts have been unsuccessful since the circuitry does not accomplish adequate multiple monitoring of the electrical condition existing between the battery and the charger and also such control circuits fail to identify a disconnection of the battery charger from the power source. The result may lead to discharge of the battery through the control circuitry and/or the battery charger circuitry.
Frequently battery charger control circuits utilize a time delay method of terminating the charging process with the result that the battery itself is not charged to the optimum potential prior to the time that the charger is disconnected from the battery. Such time delay and termination circuits frequently also require an operator to reconnect the charger to the battery thus requiring constant monitoring by an operator.